The invention is directed to systems and methods for monitoring and controlling use of medical devices.
Use of medical devices intended to treat or diagnose conditions of the body can sometimes generate stress on the material or materials from which the devices are made. The material stress can alter the physical characteristics of the devices, making future performance of the devices unpredictable.
In addition, exposure to blood and tissue during use can entrap biological components on or within many medical devices. Despite cleaning and subsequent sterilization, the presence of entrapped biological components can lead to unacceptable pyrogenic reactions.
The effects of material stress and damage caused during a single use of a medical device, coupled with the possibility of pyrogen reactions even after resterilization, reasonably justify imposing a single use restriction upon many medical devices.
The invention provides systems and methods for monitoring and controlling use of a device for treating a tissue region. The systems and methods provide the device and an element carried by the device for retaining use monitoring information. The systems and methods employ a reader to download from the element the use monitoring information to a controller for the device. The systems and methods cause the controller to process the use monitoring information by pre-programmed rules to either enable or disable operation of the device.
According to one aspect of the invention, the element retains use monitoring information as an identification code unique to the device. The pre-programmed rules cause the controller to create a table by registering unlike identification codes in memory as they are downloaded by the reader and to enable operation of the device when a new identification code is registered in the table. The pre-programmed rules cause the controller to disable operation of the device when the given identification code matches an identification code in the table.
The element can express the identification code using, e.g., a magnetic core element, or a bar code strip, or a RFID tag, or by Hall effect, or by an array of fiber optics.
According to another aspect of the invention, the element retains use monitoring information as a value reflecting time period of use of the device. The pre-programmed rules cause the controller to enable operation of the device only when the value reflects a time period of use less than a prescribed maximum time period of use.
The element can express the value using, e.g., a magnetic core element, or a bar code strip, or a RFID tag, or a stepper motor.
According to another aspect of the invention, the element includes a magnetic core carried by the device having a logic state that changes in response to use of the device. In one embodiment, magnetic flux in one direction about the core represents a logic one state and magnetic flux in another direction about the core represents a logic zero state. The core, when initially installed in the device, possesses a logic one state. Use of the device changes the logic state to a logic zero state. When the device is presented for use, the state of the core is sensed. If the core indicates a prior use (logic zero state), reuse of the device is not permitted.
According to another aspect of the invention, the element includes a latching relay carried by the device having a relay condition that changes in response to use of the device. In one embodiment, the relay is biased toward an electrically open condition. The relay can be moved and latched into an electrically closed condition. Prior to use, the relay is located in the electrically open condition. During use, the relay is moved and latched to the electrically closed condition. When the device is presented for use, the position of the relay is sensed. If the position indicates a prior use (latched closed condition), reuse of the device is not permitted.
According to another aspect of the invention, the element includes a use register carried by the device that retains a digital value that changes in response to use of the device. In one embodiment, when the device is presented for use, the value contained in the use register is sensed. If the value indicates a prior use, reuse of the device is not permitted.